In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl3/MgCl2 model catalysts with minimum Ti heterogeneity was analyzed by combined solvent fractionation and the two...

Colloidal synthesis routes have been recently used to fabricate heterogeneous catalysts with more controllable and homogeneous properties. Herein a method was developed to modify the surface composition of colloidal nanocrystal catalysts and to purposely introduce specific atoms via ligands and change the catalyst reactivity. Organic ligands adsorbed on the surface of iron oxide catalysts were ...

This article presents the fabrication of size-controllable and shape-flexible microcellular high-density polyethylene-stabilized palladium nanoparticles (Pd/m-HDPE) using supercritical foaming, followed by supercritical impregnation. These nanomaterials are investigated for use as heterogeneous hydrogenation catalysts of biphenyls in supercritical carbon dioxide with no significant surface and ...

Almost all industrial catalysts are heterogeneous, the reaction taking place on a solid surface. During the past decade homogeneous catalysts, soluble in the liquidphase reactant, have received a great deal of attention, although they have so far found only limited industrial use, chiefly because of the di$culty of their separation from the reaction products. More recently an intermediate type,...

Sima Kalhor was born in Qom, Iran in1988. He received his B.Sc. in applied Chemistry (2012) from Islamic Azad University Qom and M.Sc. in Organic Chemistry (2014) at Islamic Azad University Qom, Iran. Also, she is currently working towards her Ph.D. student in Organic Chemistry (2016) under the supervision of Prof. Mohammad Ali Zolfigol. Her research interest is the synthesis, characterization ...

Meysam Yarie was born in 1987 in Malayer/ Hamedan, Iran. He received his B.Sc. in Applied Chemistry (2010) from Malek-Ashtar University of Technology and M.Sc. in Organic Chemistry (2012) from Kurdistan University under the supervision of Dr. Kamal Amani. He is currently working towards his Ph.D. under the supervision of Professor Mohammad Ali Zolfigol. His research interest is the synthesis, c...

Stereoselectivity in alkene metathesis is a challenge and can be used as a tool to study active sites under working conditions. This review describes the stereochemical relevance and problems in alkene metathesis (kinetic vs. thermodynamic issues), the use of (E/Z) ratio at low conversions as a tool to characterize active sites of heterogeneous catalysts and finally to propose strategies to imp...

Pd/C and CoPd/C heterogeneous catalysts have been synthesized by adopting Charge Enhanced Dry Impregnation (CEDI). The particles size distribution, their high metal surface-to-bulk ratios, and synthesis feasibility are unmatchable to any known noble metal bimetallic heterogeneous catalyst preparation techniques. Next generation Fuel Cells and Fischer-Tropsch catalytic processes economy will be ...